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CONTAGIOUS PLEURO-PNEUMONIA, 



OR 



LUNG PLAGUE IN CATTLE. 



ROBERT WHITE, M. D., 

ASSISTANT SURGEON UNITED STATES MARINE HOSPITAL SERVICE. 



[Reprinted from The Boston Medical and Surgical Journal, 1879.] 



CAMBRIDGE : 

©rintcti at tl)e ilibcrjsitic '^tt^^. 

1879. 



LIBRA^RY 



OF THE 



i 



U. S. Department of Agriculture. 



Class 



rP»M«;FFR 



AUG 2^ 1910 









CONTAGIOUS PLEURO-PNEUMONIA, OR LUNG PLAGUE. 

BY KOI5ERT WHITE, M. D., 

Assistant Surgeon United States Marine Hospital Service. 

The prevalence of contagious pleuro-pneumonia among cattle at dif- 
ferent points in the Middle Atlantic States at the present time, and the 
danger of its extension by the natural course of the cattle traffic to dis- 
tricts that are now free from it, afford sufficient reason for directing 
the attention of physicians to the great injury that may result to the 
interests of agricultural communities from its spread, and for indicating 
the prominent characteristics by which the disease can be recognized, 
and the means that may be adopted for its restriction. Scientific veter- 
inary medicine has received so little encouragement in this country, 
and so few individuals have been properly trained in this specialty, that 
the services of a qualified veterinary surgeon cannot be readily obtained 
in the smaller towns and villages, where the disease is most likely to 
show itself under circumstances favoring its spread ; and it seems proper 
that physicians practicing in such districts should familiarize themselves 
with the subject to an extent sufficient to enable them to give such 
advice and direction as may save their communities from great financial 
loss, and prevent, possibly, the rrfin and distress of many families. So 
far from the observation and study of disease in animals detracting in 
any way from the dignity of the medical calling, it is presumed that 
every phj^sician of liberal training will recognize how greatly such ob- 
serA'ations have contributed in the past, and will probably contribute 
in the future, to the progress of medical science, especially in relation 
to the essential characteristics of the contagious principle in many affec- 
tions, and the manner in which disease is communicated from one in- 
dividual to another. Of the various names by which this disease has 
been designated, pulmonary/ murrain, contagious pleuro-pneumonia, and 
lung plague are those which are best known in this country. The term 
epidemic or epizootic is frequently applied in this connection, but is ob- 
jectionable, as it tends to suggest to the popular mind some determining 
influence in the atmosphere as the cause of the affection, and diverts at- 
tention from its true infectious character. As the contagious disease is 
often confounded with sporadic, non-contagious affections of the chest, I 
agree with Professor Gamgee in his preference for the term " lung 
plague " as the most distinctive, although contagious pleuro-pneumonia is 
1 



2 Contagious Pleuro-Pneumonia. 

most clearly indicative of the prevailing pathological conditions. The 
disease is indigenous in Asia and the steppes of Eastern Russia, and first 
appeared in Europe, into which it was introduced through the latter 
country, at the end of the seventeenth century, and during the succeed- 
ing hundred years it gradually spread westward, u^itil at the beginning 
of the present century outbreaks were occurring every few years over 
all parts of the continent. As the disease was extinguished in one 
place it would reappear in another, owing to the movements of cattle in 
trade. It was imported into the British Isles from Holland in 1840, and 
committed great ravages there, the average loss from destruction of cat- 
tle for many years being from ten to twenty millions of dollars. From 
Great Britain the disease was introduced into this country by various 
importations of cattle. Between 1843 and 1850 slight outbreaks oc- 
curred in the vicinity of New York and Brooklyn, which have been so 
frequently renewed as to warrant the belief that the disease has never 
been wholly extinguished there. It has appeared at different points 
along the Northern Atlantic States, but its most serious manifestation 
was at Belmont, Mass., 1859, where three cows imported from Holland 
died a few days after their arrival, and the disease extended to the other 
animals on the estate. A calf purchased from this farm showed signs 
of illness on its way to Brookfield, fifty miles distant ; it was placed in 
a barn with fifty head of previously healthy stock, most of which sick- 
ened in succession, and a large number died. The disease spread from 
farm to farm, as animals were interchanged in trade, the numerous 
deaths of cattle threatening financial ruin to many farmers, and the true 
character of the affection and the immense damage threatened to the 
agricultural interests of the State were soon recognized. The state 
authorities took prompt action by convening the legislature in special 
session, securing the necessary appropriations, and appointing commis- 
sioners with power to kill cattle actually diseased, as well as those that 
had been exposed to contagion and were suspected, the owners being 
compensated in part. Arrangements were made for the isolation and 
quarantining of diseased or suspected anim.als ; the sale or the transpor- 
tation of any cattle from the infected to the healthy districts, without 
permission of the commissioners, was made ])unishable by fine and im- 
prisonment. In spite of these energetic measures the disease was not 
completely exterminated in the State until after a hard seven-years' 
fight and the slaughter of some twelve hundred cattle, in addition to 
those which died of the disease. The history of the Massachusetts out- 
break illustrates the advantage of prompt cooperative measures for pre- 
venting the disastrous consequences that are likely to ensue from failure 
to recognize the disease in its early prevalence. /In treating of the lung 
plague it is well to insist upon the recognition of the essential fact that 
it is a specific contagious affection, whicli does not arise spontaneously, 



Contagious Pleuro-P7ieumonia. 3 

as was long supposed, from any combination of influences, like over- 
crowding, bad or swill feeding, exposure to severe weather, etc., and 
that wherever the disease has prevailed in Europe or America it has 
been introduced by some animal suffering from the specific affection. 
Its contagious character has been amply demonstrated not only by the 
difficulty of checking the disease when it has once gained a foot-hold 
among cattle, but by the experiments that have been made under the 
direction of the Swiss and French governments, where diseased animals 
were introduced among others, notably healthy, in districts where the 
affection had never prevailed, with the result of communicating it to 
nearly all the animals exposed. The greater portion of those which 
survived the disease were not again susceptible on repetition of the 
exposure. These observations also demonstrated that the contagion 
could be communicated by the clothes worn by the attendants or the 
blankets used for the animals, by the vessels and troughs from which 
they took their water and food, by the excretions, and by contact with 
the flesh of cattle that had died of the disease, and that these various 
substances retained the power of infection for many months. The 
pathological features exhibited by the disease are those of a specific and 
contagious general affection of a low typhus character, with special 
manifestations in the lungs, where extensive inflammation, with an ex- 
cessive exudation into the pleural cavity, into the bronchi, and directly 
into the lung substance itself, occurs, — conditions which may proceed to 
such an extent as directly to destroy life by interfering with respiration, 
or may be succeeded by disorganization, formation of abscesses, gan- 
grene, and more or less complete destruction of the lung tissue, accom- 
panied by purulent infection and blood poisoning. The morbid anatomy 
of the disease bears considerable resemblance to that of acute phthisis 
in the human subject ; but in many of its features the lung plague has 
a pathological analogy with small-pox, as it is eminently contagious, 
may be reproduced in other animals by inoculation with the exuded 
matter, when it causes a modified disease which secures immunity from 
its recurrence for a time, as does also an attack of the original affection. 
The special manifestations of this disease are displayed in the lungs, 
and the exudation into those organs contains the contagious principle, 
just as in small-pox the same conditions are manifested on the skin. 
The period of incubation attending the development of this affection is 
not well marked, as it may extend from one week to three or four 
months ; and even after this long incubative stage only a latent form of 
the affection, with but few characteristic symptoms, may be developed. 
The cattle which conveyed the disease from England to Australia 
were three months on the voyage, and had no symptoms of the affec- 
tion until landed, but there was no doubt that the infection of the ani- 
mals had occurred before their departure from England. These insid- 



4 Contagious Pleuro- Pneumonia. 

ions characteristics, which frequently mask its existence, add greatly to 
the difficulties connected with the disease. Many animals die during 
the first or second week, in the suffocative stage of the disease. If this 
period be survived, life may be prolonged five or six weeks. In the 
cases where recovery takes place the affected animal is capable of com- 
municating the disease to exposed healthy cattle during the whole period 
of convalescence. The disease varies greatly in intensity and in its rate 
of mortality. Animals on one farm may exhibit a mortality of seventy- 
five per cent., while on one adjoining nearly all may be sick, and but 
few die. The average death-rate is about forty per cent, of those af- 
fected. The observation of a few cases of the lung plague will enable 
any one with a medical training and a correct knowledge of the pathol- 
ogy of the affection to recognize its appearance among cattle. In a herd 
where the disease has gained a foot-hold, among the first symjjtoms 
shown by the affected animals will be the listlessness and irregularity 
of appetite and of rumination, distinguishing them from their healthy 
fellows, who are steadily browsing around them ; and it has been noted 
as a curious fact that, despite the failure of appetite, the sick animals 
have a fuller appearance than natural. Another early symptom is the 
change occurring in the animal's hide, which loses whatever softness or 
sleekness it may have possessed, and becomes rough, stiff, and staring, 
the hair tending to stand outright, and the whole coat assumes a marked 
scraggy character. Slight shiverings generally atfend the development 
of the disease, and expert dairy-maids, in some of the districts of Eu- 
rope where the plague has prevailed for a long time, recognize its 
existence at an early stage by the stiffness of the teats, the difficulty in 
milking, and the gradually lessening amount of the secretion. An ir- 
regular, slight cough, harsh and dry in character, but not painful, devel- 
ops daily ; it is attended by a short, regular moan or grunt, which 
accompanies each expiration, and forms one of the most constant and 
characteristic symptoms of the disease. Both symptoms are aggravated 
by movement, and if suspected cattle are forced into active motion the 
affected animals will generally give these signs. Pressure on inter- 
costals causes wincing and signs of tenderness ; the respirations are 
quickened, and very shallow in character. The urine is scanty and 
high colored, constipation exists, and the excrement discharged is un- 
naturally dry. Many cases of the disease undoubtedly do not proceed 
beyond the stage manifested by these symptoms, resolution of the affec- 
tion taking place, the poison being eliminated before essential change 
in the lung is produced. Although the physical examination of the 
chest in cattle is much less satisfactory than in man, on account of the 
greater thickness of the chest wall, the interposition of the broad scap- 
ulae, and the restlessness of the animals interfering considerably with 
auscultation and percussion, yet it is of great value in the diagnosis of 
the disease, and for correct observation of its progress. 



Contagious Pleuro- Pneumonia. 5' 

It does not require a veterinary expert to recognize another certain and 
constant symptom in connection witli the development of the disease, — 
tlie elevation of the temperature of the bod}^ whicii is increased from its 
normal standard, 100''-101°, to 102°-104°, and may rise to 106°. This 
increase of temperature is almost invariably marked, and the use of the 
clinical thermometer by its insertion in the rectum or vagina of sus- 
pected animals furnishes us one of the most reliable diagnostic marks 
tiiat we possess, and one that will often give indications of the exist- 
ence of the disease before the appearance of any other symptoms. An- 
imals in whom a temperature of more than 102° is recognized should 
be at once isolated and placed under observation. The flattened and 
motionless ribs on the affected side, the dullness on percussion, and the 
presence of the healthy respiratory murmur in a normal lung, or its ab- 
sence in the consolidated organ, where it may be replaced by the rales 
produced by the varying conditions of the inflamed bronchial tubes, 
or by the hollow cavernous and curoflino; sounds attending destruction 
of the lung tissue, are pathognomonic signs of the disease. Early in the 
disease, the foundation of inflammatory products on the surface of the 
pleura is indicated by the leathery friction sounds produced by the in- 
flamed surfaces rubbing over each other, and as the exudation into 
the pleural cavity increases the respiratory sounds disappear. If the 
disease progresses, the symptoms increase with more or less rapidity, 
the cough becoming more constant and severe, the respiration more 
difficult, as is shown by its quickened and spasmodic character, by the 
dilated nostrils, the arched back, and the efforts made by the animal to 
relieve the affected chest by breathing with the abdomen, drawing up 
the hind legs, throwing the body forward, the chest, owing to its pecul- 
iar construction, being thus expanded. If lying, the animal rests on 
the affected side, leaving the other as fi'ee as possible. Each expiration 
is accompanied with the characteristic moan or grunt which is present 
from the first stages, or, if absent, may be elicited by pressure on the in- 
tercostals. The dyspnoea becomes intense, and there is a free discharge 
from the widely dilated nostrils and eyes, thin and serous at first, which 
gradually becomes thick, yellow, and purulent. If in the open field, 
the sick animals separate themselves from the unaffected members of 
the herd, stand persistently with widely distended legs, and present a 
physiognomy that is very characteristic of the disease. 

. While the general temperature of the body as shown by the ther- 
mometer is greatly increased, the extremities and horns may be quite 
cold ; frequently the peculiarity being exhibited of a single horn or foot 
only being thus affected. The skin increases in harshness and dryness, 
and instead of slipping over the subcutaneous tissue as in health seems 
to become adherent to it. The pulse, which may be felt in the sub- 
maxillary artery of the jaw, or in the brachial at the inner side of the 



6 Contagious Pleura-Pneumonia. 

fore leg, is increased from its normal rate of 40 or 50 to 80 or 90, and 
is small and wiry in character. Even in health, the pulse of cattle is 
accelerated by confinement in close sheds or barns, and in disease there 
will be a corresponding increase under like circumstances. The res- 
pirations, usually 10 to 15 per minute, are increased to 35 or 40, and 
the normal relation between the pulse and respirations of 4 to 1 disap- 
pears. The signs elicited by auscultation and percussion are here of 
great value in indicating the progress of the disease. The dry frictiou 
sound at first produced by the inflamed pleura is modified as the mem- 
brane becomes roughened from the deposit of lymph on its surface, and 
still further by the filling of the cavity by the enormous exudation. 
The presence of crepitation soon indicates that not only the surface 
membrane is involved, but that the lung substance itself has also been 
invaded, and the advent of rales and sibili demonstrate that the bronchial 
passages participate in the general affection. Even wlien the consoli- 
dation is extended, it does not wholly mask the sounds produced by the 
affected pleura and bronchi. It is a disputed point whether the disease 
primarily extends from the pleura or from the bronchi to the lung sub- 
stance, but it is certain that both surfaces are seriously involved in all 
fatal cases. The dullness and tenderness elicited by percussion wull be 
in proportion to the amount of the disease. If but one lung is affected, 
the resonance is markedly increased and the respiration louder than 
natural in the other. The invasion of both lungs warrants an unfa- 
vorable prognosis. The preceding symptoms are those which accom- 
pany the active inflammatory stage, when free exudation into all parts 
of the lung is going on, which mav be checked within such limits as to 
permit of resolution or recovery in a limited number of cases, or may 
proceed to such an extent as to destroy the animal by suffocation from 
compression of the lung by the amount of pleural effusion, or from oc- 
clusion of the air cells, or even of the bronchi, by the exudation which 
is so freely poured into them, as well as by the inflammatory products 
of their own surfaces. In some cases where the consolidation is limited 
'to the central portions of the lung, the ordinary physical signs are not 
observable, and the principal symptom manifested is that of excessive 
coughing when the animal attempts to swallow. If the affection proceeds 
beyond this stage, a new train of symptoms will arise from the disintegra- 
tion that must almost necessarily ensue. The formation of abscesses, 
gangrene, and the general breaking down of the pulmonary tissue are at- 
tended with symptoms of purulent infection that are unmistakable. The 
temperature, which (hu'ing the inflammatory stage was persistently high, 
becomes variable, the breath and the discharges from the nostrils are in- 
tolerably fetid, and portions of gangrenous lung may be coughed up ; the 
animals become very weak, colliquative diarrhoea replaces the constipation 
that existed, and death is induced by exhaustion. The post-mortem ap- 



Contagious Pleuro-Pneumonia. 7 

pearances found in animals that have died of the lung plague vary greatly, 
but have the common feature of being symptomatic of a low form of in- 
flammation of the pulmonary structure, with more or less free exuda- 
tion into its substance. In animals slaughtered during the early stages 
of the disease, the pleura will be found to have lost its natural smooth, 
glistening character, to be reddened and thickened, with a varying 
amount of exudation into its cavity, and patches of yellow lymph de- 
posit scattered over its surface. In the lung substance the inflamma- 
tion exhibits the peculiar characteristic of not spreading by diffusion to 
contiguous parts, but invades separated groups of lobules at a distance 
from each other, the intervening parts retaining their normal character 
until separately attacked in their turn. This feature of the disease 
presents strong evidence in favor of its specific character, the local 
change being dependent on some general exciting cause in the blood. 
In the early stages the normal pink color of the lung is replaced by 
red, gray, or blue patches, formed by the isolated groups of consolidated 
lobules, and as the exudation occurred at different periods softening 
will be in progress in some of these, so that the conditions known as 
red and gray hepatization may exist at the same time. The affected 
portions of lung are swollen, increased in density and friability, and the 
normal resiliency, crepitation, and inflatability are lessened. With a 
little effort the parenchymatous structure may be detached from the 
interlobular tissue by which it is normally supported. The air pas- 
sages are often seriously afJected at a comparatively early period, the 
larger bronchi being lined with flaky deposits of lymph, and the smaller 
tubes quite or nearly occluded by exudation similar to that found in the 
pleural cavity, and by new elements formed from the tube-walls. Even 
the blood-vessels of the affected parts may be found obliterated by 
coagula of blood or lymph. As the disease progresses, the amount of 
effusion into the pleural cavity generally increases, but without appar- 
ent cause the quantity found will vary in different cases from a few 
ounces to several gallons. At first clear and serous in character, it 
soon becomes turbid from admixture of flaky lymph and- of pus and 
fat cells in small amount. It coagulates on cooling, so that in an ani- 
mal inspected some time after death the pleural effusion may be found 
of a gelatinous consistency. The entire pleura is thickened, mot- 
tled, and rough from the extensive deposits of lymph, and adhesive 
bands of false membrane are formed between the surfaces. These are 
sometimes so extensive as to make a sort of net-work, holding in its 
meshes the thickened flaky exudation. The strength of the adhesions 
is determined by their age and by the character of the inflammation ; 
generally they are very friable, and break down easily under the hand. 
Only in old cases, especially in such as have developed a tendency to 
recovery, do they acquire any tenacity. The pericardium becomes in- 



8 Contagious Pleuro-Pneumonia.' 

volved in tlie same manner as the pleura, and the connective tissue of 
the chest is greatly thickened from inflammatory deposits. The lung 
becomes greatly increased in bulk, in weight and density, and in friabil- 
ity from the excessive exudation going on in its substance. On sec- 
tion, it presents a marbled appearance, due to the peculiar arrangement 
of the connective interlobular tissue, which has an excessive develop- 
ment in the lungs of cattle, and distinctly marks the boundaries between 
the groups of lobules, — a prominence still farther increased in this dis- 
ease by the participation of the connective tissue in the general inflam- 
mation, and the development of new elements in its structure to such 
an extent as to cause marked thickening with formation of lymph, so 
that it may be seen traversing the lung in broad yellow stria3, irregularly 
mapping out the islands of lobules inclosed by it. Not infrequently 
the inflammatory process in the interlobular tissue is sufficiently active 
to produce suppuration and the formation of small cavities in its sub- 
stance. The disease is found in its most advanced stages in the lower 
portions of the lung, where extensive red and gray hepatization may 
exist, while the upper portion is only slightly congested or oedematous. 
On cutting into the lung and suspending it, large quantities of blood- 
stained serum will drain away. The increased density and weight of 
the lungs are made apparent by placing them in water, when they 
quickly sink ; or, better still, by weighing them in water, when the nor- 
mal weight of six or eight pounds will be found increased to twenty, 
thirty, or even forty pounds. 

Where animals that have died of the disease have been prepared for 
market, the ordinary evidences of the affection may have been removed 
by the careful sponging of the eff'usion from the chest, and trimming off 
the adhesions and lymph formations, so that a thickened pleura may be 
the only prominent sign of the disease. The most careful trimming of 
the chest walls, however, will not remove the adhesions, but the dis- 
tinction should be noted whether these are recent or old, as a certain 
number of cases of the disease tend toward resolution, and the animal 
may have lived in good condition for years after having had the disease. 
Taking in connection with the weight and density of the lung its degree 
of resiliency and inflatability, and the appearances presented on section, 
it is not difficult to decide, even after the intentional removal of the usual 
formations on the pleura and in its cavity, whether or not an animal has 
been the recent subject of contagious pleuro-pneumonia. When the 
disease proceeds to such an extent as to result in empyema, abscess, or 
gangrene of the lung, the appearances presented differ from those found 
in the human subject, under like conditions, only in degree, and the at- 
tendant phenomena of large collections of fuetid pus in the pleural sac, 
the formation of purulent cavities in the lung, and the general breaking 
down of the pulmonary tissue will be sufficiently familiar to medical 
observers without farther description. 



Contagious Pleuro- Pneumonia. 9 

The lung plague possesses some features that distinguish it from the 
iiliopatliic pleuro-pneumonia that may prevail among cattle under cer- 
tain conditions. These are its long periods of latency, its insidious 
character, its tendency to prevail in epidemic form, and the low asthenic 
type of the disease, as compared with the sudden onset, rapid develop- 
ment, and acute inflammatory symptoms of the idiopathic affection. In 
the post-mortem appearances of the latter affection the inflammation is 
of a plastic rather than of a destructive type, and is regularly diff"used 
instead of assuming the patchy form seen in the contagious disease. 
These distinctive features, however, are not sufticiently marked to form 
certain diagnostic signs, and those who are most familiar with the insid- 
ious characteristics manifested by the contagious. affection are compelled 
to admit that there are no certain means of distinction, and are disposed 
to recommend that all suspicious cases, where the origin cannot be prop- 
erly attributed to extreme conditions of weather, or other exciting 
causes, should be regarded and treated as cases of the contagious affec- 
tion. Certainly they should be so considered when there is any epi- 
demic manifestation. Treatment of the disease by medication in any 
form has been found of little benefit ; and as each animal affected be- 
comes a new centre of contagion, from which the disease maybe spread 
during the whole period of its prevalence, early isolation and slaughter 
of the infected animals, and thorough cleaning and disinfection of their 
quarters and of all articles that might carry the contagious principle, are 
the most economical and eff'ective means of dealing with it. Efforts to 
save the animals by treatment are advisa'ble only when the disease pre- 
vails to such an extent as to preclude hopes of stamping it out. The 
flesh of cattle dying in advanced stages of the disease should be deeplv 
buried, with a free supply of corrosive disinfectants, and if the hides, 
horns, and hoofs are saved healthy cattle should be carefully protected 
from exposure to them. The fluid exuded into the lungs and pleural 
cavity has the property of producing a modified affection with several 
local symptoms, when healthy animals are inoculated. Inoculation se- 
cures immunity from the disease for a period of two to four years. 
Tliis practice has been extensively pursued in countries where the dis- 
ease has gained such a foot-hold as to prevent its eradication, and it is 
only under such conditions that the practice is advisable, as each animal 
inoculated becomes a new source of contagion, from which others may 
be infected. The fact of the prevalence of the disease on the Atlantic 
coast, and the exemption which the Western States have heretofore en- 
joyed, is explained by the direction taken by the cattle traffic, which is 
almost wholly from the West toward the East. The ordinary Eastern 
cattle, among which the disease would naturally prevail, are rarely 
shipped westward, the limited number of valuable imported animals 
sent in that direction being selected and guarded with special reference 



10 Contagious Pleuro- Pneumonia. 

to securing their exemption from the disease. Should the disease, how- 
ever, once be allowed to gain a foot-hold among the vast herds of the 
West, where the conditions are such that no control could be exercised 
over the animals affected, it would probably be a permanent one, and 
result in immense injury to the agricultural interests of the country. 



LIBRARY OF CONGRESS 



002 865 235 5 





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1 



LIBRARY OF CONGRESS 



002 865 235 5. 



HoUinger Corp. 
pH8.5 



